Fire extinguisher

ABSTRACT

The specification discloses a fire extinguisher comprising a closed container having a fire extinguishing powder located therein. Spring means is provided for applying force to the wall of the container to form an opening or openings in the container when released by heat sensitive means in the presence of undesired temperatures. The heat sensitive means may be a fuse or firetrain which ignites at a relatively low temperature or a member which melts at a low temperature or a combination of the fuse or firetrain and the low temperature melting member. The spring means, when released, may be employed to open a removable cover or to rupture weakened portions formed in the container wall to allow the powder to be released and fall out of the container. The removable cover may be a lid which opens outward or a shutter which rotates to form the openings. The springs may be located on the exterior of the container or inside of the container.

United States Patent Williams [111 3,884,306 [451 May 20, 1975 FIREEXTINGUISHER [76] Inventor: Robert A. Williams, 55 Bounty Rd.

East, Forth Worth, Tex. 761 16 [22] Filed: Nov. 12, 1973 [21] Appl. No.:414,627

Primary ExaminerM. Henson Wood, Jr.

Assistant Examiner-Michael Mar Attorney, Agent, or FirmWofford, Felsman,Fails & Zobal [57] ABSTRACT The specification discloses a fireextinguisher comprising a closed container having a tire extinguishingpowder located therein. Spring means is provided for applying force tothe wall of the container to form an opening or openings in thecontainer when released by heat sensitive means in the presence ofundesired temperatures. The heat sensitive means may be a fuse orfiretrain which ignites at a relatively low temperature or a memberwhich melts at a low temperature or a combination of the fuse orfiretrain and the low temperature melting member. The spring means, whenreleased, may be employed to open a removable cover or to ruptureweakened portions formed in the container wall to allow the powder to bereleased and fall out of the container. The removable cover may be a lidwhich opens outward or a shutter which rotates to form the openings. Thesprings may be located on the exterior of the container or inside of thecontainer.

12 Claims, 27 Drawing Figures PATENTEB HAY 2 01975 SHEET 10F Jay. 7

l l I m 5 4 A tr, 3 i w B 3 4 1 E W AA 5 w M w mi PATENTED 4AY201975 3884,306

sum 2 [IF 5 PATENTED 884,306

sum 3 0F 5 PATENTED HAY 2 0 I975 SHEET 0F 5 llH'.

FIRE EXTINGUISHER SUMMARY OF THE INVENTION It is an object of thepresent invention to provide a safe, nonfragmenting fire extinguisheremploying spring means for forming an opening or openings in a containerfor releasing a fire extinguishing substance from the container andwhich has a high factor of reliability in forming the opening oropenings.

The fire extinguisher comprises a closed container having a fireextinguishing substance located in the container. In addition, there isprovided spring means biased normally to apply force to at least oneselected wall portion of the container to form an opening in thecontainer when released. There is also provide heat sensitive means forholding the spring means in its normally biased position and forreleasing the spring means upon sensing undesired temperatures to forman opening in the container to allow the fire extinguishing substance topass out of the container through the opening.

The heat sensitive means may comprise an ignitable fuse or firetrain ora holding member meltable at a relatively low temperature. In a furtherembodiment, the fuse or firetrain is employed in combination with theholding member and melts the holding member when ignited to release thespring means.

In one embodiment, the spring means is located on the outside of thecontainer for normally holding a cover in place and which is adapted tobe moved to an open position for forming an opening in the container.The spring means is normally biased in a direction to move the cover toits open position when released. In one embodiment, the cover is adaptedto move outward to form the opening, while in another embodiment, thecover is adapted to be rotated to its open position.

In a further embodiment, weakened portions are selectively formed in thewall to facilitate rupturing to form an opening in the container withoutfragmentation. The spring means is biased to normally apply an outwardforce to at least one wall portion defined by the weakened portions torupture the weakened wall portions when released. In this embodiment,the spring means may be located on the inside of the container or on theoutside of the container to rupture the container wall when released.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a fire extinguisherattached to the top of a vent-a-hood of a cooking stove;

FIG. 2 illustrates a fire extinguisher having a cover that is movedoutward by a spring when released by a holding member having a lowmelting temperature and a fuse or firetrain to allow fire extinguishingpowder to flow out of the container onto a fire;

FIG. 3 is a bottom view of the extinguisher of FIG. 2;

FIG. 4 is an enlarged cross sectional view of the spring, the holdingmember, and the fuse or firetrain;

FIG. 5 illustrates the ends of the spring;

FIGS. 6-12 illustrate different embodiments in which the spring may beheld in place and released by a low melting temperature member, anignitable fuse or firetrain, or a combination of the low meltingtemperature member and fuse or firetrain;

FIG. 13 illustrates a rotatable cover or shutter for forming openings inthe fire extinguisher container;

FIG. 14 is a cross sectional view of the holding mechanism of FIG. 13;

FIG. 15 illustrates a=fire extinguisher container hav ing weakenedportions which are ruptured by internal springs when released;

FIG. 16 is a bottom view of the extinguisher of FIG.

FIG. 21 is a fire extinguisher having weakened por- I tions which areruptured by an external spring mechanism;

FIG. 22 is an end view of the fire extinguisher of FIG. 21;

FIG. 23 is an enlarged cross sectional view of FIG. 22 taken along thelines 23-23 thereof;

FIG. 24 is a fire extinguisher having weakened portions which areruptured by another embodiment of an internal spring mechanism;

FIG. 25 is a bottom view of the fire extinguisher of FIG. 24;

FIG. 26 is an enlarged cross sectional view of FIG. 25 taken along thelines 2626 thereof; and

FIG. 27 is an alternative holding and releasing mechanism for holdingand releasing the spring for forming openings in the container.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1, there isillustrated a fire extinguisher 31 attached to the top of a vent-a hoodof a stove for providing protection against grease fires which mayoccur, for example, in a frying pan. The fire extinguisher may belocated so that it is over a given burner whereby if the heat becomestoo intense or flames flare up close to the fire extinguisher, a fireextinguishing substance will be released from the container onto thefire below to extinguish the fire.

Referring to FIGS. 2-5, there will be described one embodiment of thefire extinguisher which may be em ployed in the manner illustrated inFIG. 1. The fire extinguisher of FIGS. 2-4 comprises a closed container33 formed by a cup shaped member 35 and a removable cover or lid 37adapted to fit onto the bottom end thereof. Located within the container33 is a fire extinguishing substance 39, preferably a fire extinguishingpowder which may be of the ABC. type, or for example, of the B.C. type.As is well known, the A.B.C. type is formed of about percentmonoammonium phosphate with about 10 percent silicones and othermaterials (silica, ground mica) added to keep it free flowing and toprotect from moisture. The B.C. type is about 90-94 percent sodiumbicarbonate. The balance of the material is stearates or silicones andother materials added to keep it free flowing and to protect the sodiumbicarbonate from moisture.

The top end 35a of the container has an attaching mechanism coupledthereto which, in the embodiment disclosed, is a magnet 41 whereby thefire extinguisher may be attached to and hung from a metallic object,for

example, to the top of the vent-a-hood above the stove to allow thecover 37 to face downward above the burner or burners of the stove. Thecover 37 normally is held in place by a spring 43 which is released toopen the cover when the temperature becomes too high, for example, dueto a flame resulting from a grease fire. When the cover is opened orremoved, the fire extinguishing powder then will fall out of thecontainer onto the fire. Barrier strips 45 are provided to control theflow of the powder so that it does not fall out in one lump, but allowsit to gently fall out continuously for about seconds, in one embodiment.The cover 37 has edges 37a which fit against the edges 35b of thecontainer to close the container when the cover is in place. The spring43 has one end 43a attached to the cover 37 and its other end 43bunfolded in a direction opposite its normal coiled position and wrappedaround the container where it is held by a holding arrangementcomprising a washer shaped member 51 which is characterized by a lowmelting temperature. As seen in FIG. 5, the end 43a of the spring has anaperture 430 formed therethrough and into which is inwerted two eyelets53 and 55. Eyelet 53 attaches the spring end 43a to the cover while theeyelet 55 is inserted through eyelet 53 and through aperture 51a ofmember 51 and attaches the low melting temperature member 51 to thecover outside of the container and at a point spaced from the cover. Thefree end 43b of the spring is fitted under the member 51 and hence isrestrained by the member 51. Also inserted through the eyelet 55 is afuse or firetrain 57 which has a low flame temperature ignition point.In operation, a low temperature flame will ignite the fuse 57 which inturn will cause the member 51 to melt to release the free end 43b of thespring 43, which then wil coil over the top of the container and overthe side of the container and up to the top of the container. Since thefree end 43b of the spring 43 clears the cover 37, the other end 43a ofthe spring which is fastened to the cover by the way of eyelet 53attempts to regain its shape and instantaneously removes the lid orcover 37 thereby allowing the powder 39 to fall out of the containeronto the fire.

The member 51 has a very narrow temperature range between its solid andmolten state and in one embodiment, has an eutectic melting temperatureof 255F, eutectic meaning that it has a rather sharply defined meltingtemperature. The member 51 is an alloy which is commercially availableand in one embodiment, has a composition of bismuth 55.5 percent andlead 44.5 percent. In another embodiment, it may have a composition ofbismuth 58 percent and tin 42 percent, with a eutectic meltingtemperature of 281F. The fuse 57 is more susceptible to a quick flamethan the member 51 and in one embodiment, may be of the type disclosedand claimed in my US. co-pending application, Ser. No. 414660, filed thesame date as the present application. By employing the combination ofmember 51 and the flame sensitive fuse 57, the releasing mechanism islow temperature flame sensitive, as well as being temperature sensitivein that the member 51 itself will melt and release from heat alonewithout flame. If desired, the fuse 57 may be eliminated whereby onlythe holding member 51 is employed to hold and release the spring. Inthis embodiment, the eyelet 55 will be closoed.

The barrier 45 comprises four spaced arms extending outward within thecontainer near the bottom end and having their base ends 45a attached tothe top end 35a of the container 35 by way of a rivet illustrated at 61.On the top side of the container, a ring 63 is attached to the rivet andto a case 65 holding the magnet 41 to allow movement of the containerrelative to the magnet. As illustrated, the ring 63 extends throughaperture 61a formed through the exterior end of the rivet 61 and throughaperture 67 extending through the exterior end of a rivet 69 attached tothe magnet case 65. If desired,

the magnet may be removed to allow the fire extinguisher to be attachedwith nails or staples to a wooden member by way of the ring 63. In thisembodiment, the fire extinguisher may be attached and hung from therafters of a roof for fire protection purposes.

In one embodiment, the spring 43 is a stainless steel continuouslypre-formed spring, pre-formed to a continuous diameter of 0.375 whichtends to coil upon itself when released. As shown in FIG. 4, a lightcoating 71 of nitrocellulose may be applied around the fuse 57 on theinterior side of the cover 37 to enhance burning. The container 33comprising member 35 and cover 37 are formed of aluminum. There is nowater-proof seal between the cover 37 and member 35 except duringshipping or storage which is accomplished by a pull-tab shrink sleeve73. When the tire extinguisher is to be employed for protection againstfire, the sleeve 73 will be pulled off before the fire extinguisher ismounted in place to allow the fire extinguisher to function as intended.

As disclosed in my co-pending application, the fuse disclosed andclaimed therein comprises a thin copper wire heavily coated with a fastburning substance or material which contains, in essence, 2 3 micronsize fine silicon powder for fuel ranging from 30 to 60 percent, andlead peroxide (PbO ranging from 30 to 60 percent as an oxidizer plus. 5to 10 percent fine zinc powder to add to the heat of the burning andacetone wetted cellulose nitrate used to bind these materials together.The ratios of this formulation may be varied to produce differentburning rates and this formulation is extremely stable. Wrapped aroundthe fast burning substance is a protective covering comprising spirallywrapped wires which may be formed of glavanized soft iron. Spirallywrapped around the wires in a counter direction is a nylon yarn.Deposited on the yarn, and hence on the cover is a coating ofnitrocellulose for environmental protection and which also provides highflammability. The purpose of the inner copper wire is to provide supportfor the fuse and continuity of burning since it has a high thermalconductivity. The fast burning substance around the copper wire enablesthe fuse to burn rapidly. The cover comprising the spirally wrapped wireand yarn prevent the fuse from being extinguished or destroyed in itsburning process. The purpose of the outer coating of nitrocellulose isfor environmental protection and also provides a high flammability asindicated above. The ends of the fuse are cut at an oblique angle ofabout 45 relative to the axis of the fuse to provide a sharp pointed tipto allow the highly flammable outer coating, which is also applied tothe cut ends, to ignite easily and to provide a large surface on theends to facilitate burning of the highly flammable coating whereby thefuse may be ignited readily by a low temperature flame.

Referring now to FIGS. 6-12, there will be described different ways inwhich the spring 43 may be held in place for confining the cover 37. Inthe embodiment of FIGS. 6 and 7, the'end 43a of the spring is secured tothe cover 37 by way of a rivet 81. The tips of both ends of the spring43 have apertures 83 and 85 extending therethrough. A wire strand 87 maybe formed of a low temperature melting alloy mentioned above or it maybe a wire fuse, for example, of the type known as Pyro- Fuse. This fusealso may be ignited by a low temperature flame. It is available instrand or wire form and is bi-metallic having an outer shell formed ofpalladium and an inner core of aluminum. It is manufactured by Pyro-FuzeCorporation, an affiliate of Sigmun Cohn Corporation, 121 S. ColumbusAve., Mount Vernon, NY. 10553.

In the embodiment of FIGS. 8 and 9, the end 43a of the spring 43 issecured to the cover 37 in the same manner as shown in FIG. 4, however,the low melting temperature member 51 is elongated and has an aperture91 formed in its extending end and the spring end 43b has a narrowed end92 inserted through the aperture 91.

In the embodiments of FIGS. -12, the spring end 43a is secured to thecover 37 by way of a rivet 81. Both ends 43a and 43b are narrowed andare inserted through apertures 93 and 94 formed through a low meltingtemperature member 95. If desired, a U-shaped fuse 96 which is lowtemperature flame sensitive may be inserted through apertures 97 and 98formed through member 95. The fuse 96 may be of the type disclosed andclaimed in my co-pending application mentioned above.

Referring now to FIGS. 13 and 14, the cover employed is a rotatableshutter 101 which is pivotally coupled for rotation to the end wall 103secured to the container sides 35 by a water-proof double seam. Thecontainer wall 103 has three openings 105-107 shown in dotted lineswhile the shutter 101 has three openings 115-117. In FIG. 13, theshutter 10] is shown in its closed position whereby portions 118-120 ofthe shutter overlay and close the openings 105-106, formed in the wall103. The shutter is adapted to be rotated clockwise to align openings115-117 with openings 105-106 to allow the fire extinguishing powder tofall out of the container. In the open position, the sections of thewall 103 and of the shutter 101 between the aligned openings control theflow of the fire extinguishing powder from the container to allow it togently fall out for a period, in one embodiment,, of about 10 secends.

The shutter 101 is pivotally coupled to the wall 103 by way of a rivet121 which is inserted through an eyelet 123. Also located around therivet 121 is a sleeve 125 around which is located a coil spring 127shown under tension in FIG. 13. One end 127a of the spring 127 issecured to a rivet 129 which in turn is secured to the wall 103. Therivet 129 extends through opening 115 of shutter 101. The other end12712 of the spring 127 is secured to a rivet 131 which in turn issecured to the shutter 101. A low melting temperature member 133 issecured to the tops ends of the two rivets 129 and 131 for restrainingthe spring and hence holding the shutter 101 in its closed position.Extending through two apertures formed in member 133 is a U- shaped fuse135 which is low flame temperature sensitive. This fuse may be the sameas fuse 96 described with respect to the embodiment of FIGS. 10-12. Inoperation, when the fuse 135 is ignited, the member 133 melts to releasethe spring 127. When this occurs, the spring end 127b will expandclockwise to rotate the shutter 101 clockwise to align apertures 115-117respectively with apertures 105-107. If desired, the fuse 135 may not beemployed.

Referring now to FIGS. 15-20, the container 33 has an end wall 141secured to its sides 35, by a waterproof double seam. Formed in the wall141 are scored lines or weakened portions 143-146 which may be rupturedby applying force to the wall portions 153-156 to form openings throughthe wall 141 to allow the fire extinguishing powder to pass outward.Located within the container 33 are four spring members 161, each ofwhich is similar in shape to a safety pin. Each spring 161 has one end161a held in place by a square ferrule 165 and a hat shaped member 167.As illustrated, the member 167 has groove 169 formed therein into whichare inserted the ends 16111 of the springs. The ferrule 165 then isslipped over the member 167 with the springs in place and the tabs 171wrapped onto the base of the ferrule 165 to secure the springs in place.The other ends 161b of the springs 161 engage the pointed ends of thetear-open sections 153, 154, 155, and 156 to normally apply an outwardforce against these sections. Extending through the bottom of the member167 are inner and outer eyelets 173 and 175. The outer eyelet 175secures the hat shaped member 167 to the container end 141 while theinner eyelet 173 secures a low melting temperature member 177 against awasher 179 to hold the washer 179 against the exterior of the wall 141.As illustrated, the peripheral edges of the washer 179 extends over thetips or pointed ends of the tearout sections 153-156. Thus, as long asthe low melting temperature member 177 holds the washer 179 in place,the springs 161 are prevented from rupturing the weakened portionsdefining the sections 153-156. Extending through the inner eyelet 173 isa low temperature flame ignitable fuse 57 as described previously. Thelow temperature melting member 177 may be the same low temperature alloyas described previously. In operation, when the fuse 57 ignites, it willcause the member 177 to melt thereby releasing the restraining forceagainst the washer 179, whereby the washer 179 is free to move outward.When this occurs, the force of the springs 161 is released therebycausing the spring arms 16111 to expand outward thereby rupturing theweakened portions 143-146 and hence causing the tear-out portions153-156 to be forced outward, without fragmentation, to form openings inthe wall 141 to allow the fire extinguishing powder to drop outward ontoa fire below. Preferably the container member 35 and wall 141 will beformed of aluminum. It is to be understood that the low meltingtemperature member 177 is sensitive to heat as indicated above and willmelt when the temperature becomes sufficient even though there is noflame sufficient to ignite fuse 57. In addition, if desired, the fuse 57may be eliminated. In this instance, the eyelet 173 employed will be aplugged eyelet.

Referring now to FIGS. 21-23, there will be described an embodimentwherein springs are located on the exterior of the container forrupturing wall portions defined by weakened portions or grooves forforming openings in the container. In FIG. 22, the spring assembly isidentified at 201 and comprises a spring plate having four springsections 203-206 with parallel sides and pointed ends extending inwardwithin the heart shaped cutout sections 207-210. The outer edge of theassembly 201 is attached by rivets 211 to the exterior side of thecontainer wall 212 which is sealed to the container member 35 by awater-proof double seam. The central portion of the spring assembly 201is at- '7. d tached to the container wall 212 by way of an eyelet 217.Formed in the wall 212 of the container are tearout or rupturablesections formed by weakened or grooved-lines in the wall 212 whichcorrespond with the patterns of the heart shaped cutout sections207-210. In'FIG. 23, the grooved lines forming these pull out sectionsare.illustrated at 219. The inner against a washer 227. Fuse 229 extendsthrough eyelet 223. The peripheral edges of the washer 227 overlays thepointed ends of the spring members 203-206 and prevents the springmembers from moving outward as long as the member 225 and washer 227 arein place. Normally the spring members 203 will be formed so that theywill be biased in an outward direction against the pointed ends of thetear-out portions 233-236.

Thus the member 225 and washer 227 normally prevent the springs 203-206from rupturing the weakened portions of the wall 212. When the fuse 229ignites, the

2 member 225 melts whereby releasing the washer 227.

-When this occurs, the force of the springs 203-206 is sufficient torupture the weakened or scored portions thereby pulling the tear-outsections of the wall 212 outward to formopenings in the wall to'allowthe fire extinguishing powder to escape.

The holding and releasing mechanism for holding the spring members inplace comprise aninner eyelet 223 inserted within eyelet 217 and whichholds a low melting temperature member 225 against a washer 227. As

being pulled outward when the washer is in place. Ex-j tending throughthe inner eyelet'217 is a low temperature flame sensitive fuse 229. Thefuse 229 may be the same as fuse 57 described in the embodiments ofFIGS.

1-5, while the washer 225 may be'the same as washer 51 described in theembodiment of FIGS. l-5. In operation, when the fuse 229 ignites, themember 225 melts thereby releasing the washer 227 and allowing thesprings 203-206-to spring outward and rupture the weakened portionsof'the wall 212 thereby pulling the tear-out sections outward to formthe desired openings. In FIG. 21, three tear-out sections pulled outwardby springs 204, 205, and 206 are illustrated a234,- 235, and 236. It isnoted that when the tear-out sections-are pulled outward, their outerends remain connectedlto the container wall 212. g Y

As illustrated in FIG. 23,. the washer 217 also clamps an internalspring washer 237 against the inside'heads of the rivets 221.. Thepurpose of the internal spring washer 237 is to apply additional loadingagainst the rivets 221 to start the'tearing action of'the tear-outsections from the wall 212 when the member 225 melts and the washer 227is released. In FIG. 23, a thin coating 239 of nitrocellulose is appliedaround the fuse on the inside of the container to facilitate burning andignition.

Referring now to FIGS. 24-26, an internal spring is employed forrupturing weakened or scored lines of the wall and forcing tear-outsections outward to form the desired openings in the container. Thespring assembly is identified at 201 in FIG. 24 and has the same shapeas that illustrated in FIG. 22, however, it is attached to the inside ofthe wall 212 which is illustrated in FIG. 25 and has the same shape andform as the wall 212 of FIGS. 21-23. The wall 212 is attached to thesides of the container by a water-proof double seam. The outer edge ofthe spring assembly 201 is attached to the inside of the wall 212 byrivets illustrated at 211. Eyelet 217 attaches the central portion ofthe spring assembly to the wall 212 as illustrated in FIG. 26 whileeyelet 223 holds the low temperature melting member 225 of the wallthereby forcing the tear-out sections 233-236 outward to form thedesired openings to allow the fire extinguishing powder to pass outward.

FIG. 27 illustrates an arrangement for holding the springs 203-206 inplace and then releasing the springs without the use of the fuse 229. Inthis embodiment, in-

stead of eyelet 223, a semi-tubular rivet 243 is employed to secure amultipointed low melting temperature member 245 against the washer 227to prevent the force of the springs 203-206 from rupturing the scoredportions and forcing the tear-out sections outward. When the member 245melts, the washer 227 will be released to allow the springs 203-206 torupture the scored portions and force the tear-out sections outward toform the desired openings. It is to be understood, that the rivet 243and low temperature melting member may be employed in the embodiments ofFIGS. 24-26 in lieu 'of the eyelet 223 and fuse 229.

In the embodiment of FIGS. 24-27, the tear out sections 233, 234, 235,and 236 may be removed thereby forming openings in the wall 212. Theopenings will be I covered by a thin and breakable circular disc locatedon the inside of the wall 212. The pointed ends of the springs 203-206will bear against the'disc at points opposite the washer 227. When thefuse 229 ignites and the member 225 melts and the washer 227 isreleased, the force of the springs will rupture the disc through theopenings thereby allowing the powder to fall out of the container ontothe tire below. In one embodiment, the breakable disc may be formed ofaluminum foil.

I claim 1. A fire extinguisher comprising:

a closed container,

a fire extinguisher substance located in said container,

spring means biased normally to apply force to at least one selectedwall portion of said container to form an opening in said container whenits force is released,

a meltable holding member for normally holding said spring means in itsnormally biased position and for releasing said spring means when saidholding member melts, and

a heat sensitive fuse or firetrain adapted to ignite in the presence oftemperature of a given intensity to apply heat to said holding member toallow'said member to melt and release said spring means to form anopening in said container to allow said fire extinguishing substance topass out of said container through said opening.

2. The fire extinguisher of claim 1 wherein said spring means is locatedon the outside of said container.

3. The tire extinguisher of claim 2 wherein: Y

said selected wall portion comprises a cover adapted to be moved to openand closed positions for forming said opening and for closing saidcontainer,

said spring means being normally biased in a direction to move saidcover to its open position when said spring means is released.

4. The fire extinguisher of claim 3 wherein said cover is adapted tomove outward to form said opening.

5. The fire extinguisher of claim 4 wherein said spring means has oneend held by said holding member and is wraped around said container andhas its other end attached to said cover.

6. The fire extinguisher of claim 3 wherein said cover is adapted to berotated to its open position.

7. The fire extinguisher of claim 6 wherein said spring means has oneend coupled to a stationary wall portion of said container and its otherend coupled to said cover for rotating said cover to its open position.

8. The fire extinguisher of claim 2 wherein:

said selected wall portion is formed by weakened wall portionsselectively formed to facilitate rupturing to form an opening in saidcontainer without fragmentation,

said spring means is biased to normally apply an outward force to saidselected wall portion to rupture said weakened wall portions when saidholding member melts to form said opening in said container.

9. The fire extinguisher of claim 1 wherein said spring means is locatedon the inside of said container.

10. The fire extinguisher of claim 9 wherein:

said selected wall portion is formed by weakened wall 10 portionsselectively formed to facilitate rupturing to form an opening in saidcontainer without fragmentation,

said spring means is biased to normally apply an outward force to saidselected wall portion to rupture said weakened wall portions when saidholding member melts to form said opening in said container.

11. A fire extinguisher comprising:

a closed container,

a fire extinguishing substance located in said container,

force producing means biased normally to apply force to at least oneselected wall portion of said container to form an opening in saidcontainer when its force is released,

a meltable holding member for normally holding said force producingmeans in its normally biased position and for releasing said forceproducing means when said holding member melts to form an opening insaid container to allow said fire extinguishing substance to pass out ofsaid container through said opening, and

a heat sensitive fuse or firetrain adapted to ignite in the presence oftemperature of a given intensity to apply heat to said holding member toallow said holding member to melt to release said force producing means.

12. The fire extinguisher of claim 11 wherein said holding member ischaracterized by a narrow temperature range between its solid and moltenstate.

1. A fire extinguisher comprising: a closed container, a fireextinguisher substance located in said container, spring means biasednormally to apply force to at least one selected wall portion of saidcontainer to form an opening in said container when its force isreleased, a meltable holding member for normally holding said springmeans in its normally biased position and for releasing said springmeans when said holding member melts, and a heat sensitive fuse orfiretrain adapted to ignite in the presence of temperature of a givenintensity to apply heat to said holding member to allow said member tomelt and release said spring means to form an opening in said containerto allow said fire extinguishing substance to pass out of said containerthrough said opening.
 2. The fire extinguisher of claim 1 wherein saidspring means is located on the outside of said container.
 3. The fireextinguisher of claim 2 wherein: said selected wall portion comprises acover adapted to be moved to open and closed positions for forming saidopening and for closing said container, said spring means being normallybiased in a direction to move said cover to its open position when saidspring means is released.
 4. The fire extinguisher of claim 3 whereinsaid cover is adapted to move outward to form said opening.
 5. The fireextinguisher of claim 4 wherein said spring means has one end held bysaid holding member and is wraped around said container and has itsother end attached to said cover.
 6. The fire extinguisher of claim 3wherein said cover is adapted to be rotated to its open position.
 7. Thefire extinguisher of claim 6 wherein said spring means has one endcoupled to a stationary wall portion of said container and its other endcoupled to said cover for rotating said cover to its open position. 8.The fire extinguisher of claim 2 wherein: said selected wall portion isformed by weakened wall portions selectively formed to facilitaterupturing to form an opening in said container without fragmentation,said spring means is biased to normally apply an outward force to saidselected wall portion to rupture said weakened wall portions when saidholding member melts to form said opening in said container.
 9. The fireextinguisher of claim 1 wherein said spring means is located on theinside of said container.
 10. The fire extinguisher of claim 9 wherein:said selected wall portion is formed by weakened wall portionsselectively formed to facilitate rupturing to form an opening in saidcontainer without fragmentation, said spring means is biased to normallyapply an outward force to said selected wall portion to rupture saidweakened wall portions when said holding member melts to form saidopening in said container.
 11. A fire extinguisher comprising: a closedcontainer, a fire extinguishing substance located in said container,force producing means biased normally to apply force to at least oneselected wall portion of said container to form an opening in saidcontainer when its force is released, a meltable holding member fornormally holding said force producing means in its normally biasedposition and for releasing said force producing means when said holdingmember melts to form an opening in said container to allow said fireextinguishing substance to pass out of said container through saidopening, and a heat sensitive fuse or firetrain adapted to ignite in thepresence of temperature of a given intensity to apply heat to saidholding member to allow said holding member to melt to release saidforce producing means.
 12. The fire extinguisher of claim 11 whereinsaid holding member is characterized by a narrow temperature rangebetween its solid and molten state.